A conventional utility electric power generating facility supplies electric power to electric power users over a vast and expansive electric power distribution grid containing many interconnected electric power line networks. The power line networks, which can be of various sizes, convey low, medium or high voltage electric power. Each of the networks includes such power transmission equipment elements as overhead electric power transmission wires, electric power transmission line connectors, surge arrestors and step-down electric power transformers.
Maintenance of the power line networks from which a larger power distribution grid is constructed is a major and ongoing effort. Each of the individual power networks of the grid usually contains a large number of power equipment elements that can conceivably fail in part or completely for a variety of causes, which include exposure to the external environment and end of useful life, to create a partial or complete discontinuity in the network at the element. When a power network element experiences a predetermined failure level, a fault is created in a power line network at the element that prevents satisfactory transmission of electric power downstream of the location of the fault, thereby cutting off the supply of electric power to downstream power users.
Power equipment components can fail either gradually or substantially instantaneously to create a fault in a power line network. A substantially instantaneous fault can be created, for example, upon the complete severing of a connection between a transmission wire and another transmission wire or power wire connector, such as may occur when a utility pole to which a transmission wire is connected falls in a storm. The power company typically learns of this fault from the power user, who no longer is receiving electric power service, soon after the fault initially occurs.
A power company, however, does not usually become aware of a gradual equipment failure, which may eventually become a fault, until the failure becomes so severe that a fault actually occurs. Consequently, the power company does not have the necessary information to perform preventive maintenance on the failing element before the fault occurs. For example, a power transformer, which is known to degrade gradually over time, may begin to operate at less than an optimal level, yet still operate at a level that permits a satisfactory, uninterrupted supply of electric power to downstream power users. In this circumstance, the downstream power users continue to have satisfactory power service while the operating level of the transformer is initially degrading. The power users, therefore, do not notify the power company of any problem with power service. Thus, the power company is not aware of an existing or worsening equipment failure and the potential that the equipment failure can eventually become a fault. Ultimately, an insulation failure in the transformer equipment may develop into a major failure event or fault in the power network. The power company, however, typically learns that the transformer equipment has reached the end of its useful life only after a fault in the network is created.
Therefore, a need exists for method and system for obtaining information concerning operating status of power line network elements and using the element operating status information to detect and identify the location of an existing or anticipated (future) fault in the network.